| 摘要 |
PURPOSE:To accurately detect the residual amt. of the ink in an ink tank without bringing about the cost increase of the ink tank by directly detecting the presence of the ink in an ink introducing part at least a part of which is constituted of a light-transmitting member by use of optical sensor. CONSTITUTION:In an ink jet printer selectively emitting ink droplets to printing paper to perform printing, an ink tank 2 opened to the air and an ink introducing part 8 at least a part of which is constituted of a transparent or translucent member 9 are provided. The presence of the ink 6 in the ink introducing part 8 is detected by a reflection type optical sensor 12 to detect the residual amt. of the ink. As a result, the residual amt. of the ink in the ink tank can be accurately detected under any conditions without bringing about an increase in the cost of the ink tank becoming disposable. |
